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A kind of preparation method of aluminate for impregnated diffusion cathode

An aluminate and cathode technology, which is applied to the preparation field of a room temperature solid-phase method, can solve the problems of serious environmental pollution and difficult mixing of raw materials, and achieves the effects of high preparation yield, low cost and environmental friendliness.

Active Publication Date: 2020-12-29
KUNSHAN GUOLI VACUUM ELECTRIC
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The mechanical mixing method uses BaCO 3 , CaCO 3 and Al(OH) 3 It is a method to obtain aluminate precursor by mixing the raw materials by ball milling method. During the mixing process, the raw materials do not undergo chemical reactions, that is, the composition of the precursor after ball milling is the same as that of the raw materials; the main disadvantage of this method is that the raw materials are difficult to mix evenly ; while the liquid-phase co-precipitation method is to Ba(NO 3 ) 2 , Ca(NO 3 ) 2 4H 2 O and Al(NO 3 ) 3 9H 2 O and other raw materials are dissolved in water to make a solution, and an excessive amount of precipitating agent is added to react to obtain an aluminate precursor; the method has mild reaction conditions and is easy to control, but a large amount of aqueous salt solutions are used, causing serious environmental pollution.

Method used

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  • A kind of preparation method of aluminate for impregnated diffusion cathode
  • A kind of preparation method of aluminate for impregnated diffusion cathode
  • A kind of preparation method of aluminate for impregnated diffusion cathode

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Example 1: 612 aluminate prepared by solid state method at room temperature and its electron emission properties

[0022] Experimental conditions: first weigh 30g of Ba(NO 3 ) 2 , press Ba(NO 3 ) 2 : Ca(NO 3 ) 2 4H 2 O: Al(NO 3 ) 3 9H 2 The molar ratio of O is 6:1:4 and the Ca(NO 3 ) 2 4H 2 O and Al(NO 3 ) 3 9H 2 The mass of O; then calculated to make Ba 2+ , Ca 2+ and Al 3+ Completely precipitated cations (NH 4 ) 2 CO 3 The mass of precipitant (molar ratio Ba(NO 3 ) 2 :(NH 4 ) 2 CO 3 = 0.2). In order to ensure that the Ba 2+ , Ca 2+ and Al 3+ All cations precipitated, in this example (NH 4 ) 2 CO 3 The actual weighing mass is 43.5g. Put the above raw materials into an agate jar, and add 15ml of alcohol; use a planetary ball mill to fully mix and react; during the ball milling process, the ball-to-material ratio is 20:1, the rotation speed is 200 rpm, and the ball milling time is 1 hour. After the ball milling, the obtained sample was fi...

Embodiment 2

[0026] Example 2: 512 aluminate prepared by room temperature solid-phase method and its electron emission properties

[0027] The experimental conditions are the same as in example 1, the difference is that Ba(NO 3 ) 2 : Ca(NO 3 ) 2 4H 2 O: Al(NO 3 ) 3 9H 2 The molar ratio of O is 5:1:4. The X-ray diffraction data are attached figure 2 . Through the comparison of phase analysis software, it can be seen that the aluminate only contains Ba 5 CaAl 4 o 12 Mutually. where Ba 5 CaAl 4 o 12It is an effective electron emission active material.

[0028] Preparation of the test cathode: the cathode substrate is made of tungsten sponge with 25% pores, the cathode substrate and the molybdenum support cylinder are brazed with molybdenum ruthenium brazing filler metal at high temperature (1980°C), the heater is placed in the molybdenum support cylinder, and filled with alumina Powder, sintered at high temperature (1700°C); put the cathode substrate upside down in 512 alumi...

Embodiment 3

[0030] Embodiment 3: 532 aluminate and its electron emission performance of room temperature solid state reaction method

[0031] The experimental conditions are the same as in example 1, the difference is that Ba(NO 3 ) 2 : Ca(NO 3 ) 2 4H 2 O: Al(NO 3 ) 3 9H 2 The molar ratio of O is 5:3:4. The X-ray diffraction data are attached image 3 . Through the comparison of phase analysis software, it can be seen that the aluminate contains Ba 5 CaAl 4 o 12 phase and a small amount of CaO phase. where Ba 5 CaAl 4 o 12 It is an effective electron emission active material.

[0032] Preparation of the test cathode: the cathode substrate is made of tungsten sponge with 25% pores, the cathode substrate and the molybdenum support cylinder are brazed with molybdenum ruthenium brazing filler metal at high temperature (1980°C), the heater is placed in the molybdenum support cylinder, and filled with alumina Powder, sintered at high temperature (1700°C); put the cathode substr...

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Abstract

The invention provides a preparation method of aluminate for impregnating diffusion cathode, which adopts a room temperature solid-phase reaction method to prepare aluminate precursor. The method is suitable for the preparation of aluminates such as active materials 612, 411, and 532 for electric vacuum devices, and the prepared aluminates have high emission current density. Compared with the mechanical mixing method, different raw materials are used, which not only play a role in mixing during the ball milling process, but also generate new substances through chemical reactions; compared with the liquid phase precipitation method, no aqueous solution is used, which greatly reduces environmental pollution. The method has high preparation yield, less pollution, low cost, is environment-friendly, and does not need a solvent, and is a simple, environment-friendly and easy-to-industrial method.

Description

technical field [0001] The invention relates to a method for preparing an aluminate for impregnating and diffusing cathodes, in particular to a method for preparing an aluminate precursor using a room-temperature solid-phase method. Background technique [0002] Vacuum electronic devices play an important role in national economic fields such as radio, television, radio communication, space navigation, electronic countermeasures, and modern industrial induction heating. As the electron emission source of the vacuum device, the performance of the cathode has a crucial influence on the power output, stability, reliability and lifetime of the device. At present, barium tungsten cathode is the most commonly used hot cathode in vacuum electronic devices, but there is still a large gap between the emission performance of barium tungsten cathode materials in my country and foreign countries, which is mainly reflected in the preparation process of aluminate. However, the methods fo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/16H01J23/04
CPCC01F7/16C01P2002/72C01P2006/40H01J23/04
Inventor 付浩方健郑强
Owner KUNSHAN GUOLI VACUUM ELECTRIC